<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>absolute三栏布局</title>
    <style>
        .parent {
            position: relative;
            height: 40px;
        }

        .parent>div {
            height: 100%;
        }

        .left {
            position: absolute;
            left: 0;
            top: 0;
            width: 100px;
            background: skyblue;
        }

        .right {
            position: absolute;
            right: 0;
            top: 0;
            width: 100px;
            background: skyblue;
        }

        .middle {
            position: absolute;
            top: 0;
            left: 100px;
            right: 100px;
            background: yellowgreen;
        }
    </style>
</head>

<body>
    <div class="parent">
        <div class="left"></div>
        <div class="middle"></div>
        <div class="right"></div>
    </div>
</body>

</html>